Diabetes drugs sold by Merck & Co. (MRK) and Bristol-Myers Squibb Co. (BMY) may double a user’s risk of developing an inflammation of the pancreas linked to cancer and kidney failure, an analysis of insurance records shows. Patients hospitalized with pancreatitis were twice as likely to be taking Januvia, Merck’s top-selling drug, or using Bristol-Myers’s Byetta, than a control group of diabetics who didn’t have pancreatitis, according to the analysis today in the journal JAMA Internal Medicine. Both drugs increase GLP-1, a hormone that stimulates insulin production from the pancreas. Doctors have been concerned that this category of diabetes treatments may damage the pancreas since the U.S. Food and Drug Administration said in 2007 it received a high number of reports of pancreatitis in patients taking Byetta. The agency issued a similar alert for Januvia in 2009. The study, which analyzed data from 2005 to 2008, showed a doubling in pancreatitis cases. “This is the first real study to give an estimate of what the risk is, until now we just had a few case reports,” said Sonal Singh, the study’s author and an assistant professor of medicine at Johns Hopkins University in Baltimore. “These drugs are effective in lower glucose, but we should also consider the risk of pancreatitis and balance the risk versus the benefit.” Merck, the second-largest U.S. drugmaker, reported $4 billion in sales, or about 9 percent of total revenue, from Januvia last year. The daily pill blocks an enzyme that breaks down GLP-1. Janumet, which combines Januvia with the older diabetes drug metformin, generated $1.7 billion in sales last year for Whitehouse Station, New Jersey-based Merck. Novo’s Victoza: Bristol-Myers, based in New York, acquired Byetta when it bought Amylin Pharmaceuticals last year for about $5 billion. Byetta, which mimics GLP-1, had sales of $148 million for Bristol-Myers last year, and $159 million for Indianapolis-based Eli Lilly & Co. (LLY), which ended its marketing partnership with Amylin in 2011.